Start by crushing an entire package of Oreo cookies (this is about 36) with a food processor or just crushing by hand. You want fine cookie crumbs!
Mix the cookie crumbs with 6 tablespoons melted butter until well blended. Evenly spread and lightly press mixture to a 9 x 13 inch baking dish. Put the pan in the refrigerator while you work on the additional layers.
Mix the cream cheese with a mixer until light and fluffy. Add in 2 Tablespoons of milk, and sugar, and mix well. Stir in 1 and 1/4 cups Cool Whip. Carefully spread this mixture over the crust with a spoon or spatula.
In a bowl, combine chocolate instant pudding with 3 and 1/4 cups cold milk. Whisk for several minutes until the pudding starts to thicken OR just put the pudding and milk into a sealed Tupperware container and shake vigorously until it’s all mixed. Use a spatula to spread the mixture over the previous cream cheese layer. Allow the dessert to set for about 5 minutes so that the pudding can firm up.
Spread the remaining Cool Whip over the top. Sprinkle mini chocolate chips evenly over the top. Place in the freezer for 1 hour or the refrigerator for 4 hours before serving.